While this subject isn't directly related to TenFourFox, I can relate to your problem. Just a short answer: Usually any printer connected via USB should work with at least basic functionality using the built-in Gutenprint drivers of Mac OS X 10.5. You do not need to install drivers or software supplied by the manufacturer. If it's a printer-scanner, the scanning device should work using Image Capture.app if it has a TWAIN compatible interface. Just buy a simple printer with no shinanigans and you should be fine.